1. Field of the Invention
The present invention relates to voice mail systems configured for providing messaging services for subscribers in a voice over Internet Protocol (IP) network according to H.323 protocol.
2. Description of the Related Art
The evolution of the public switched telephone network has resulted in a variety of voice applications and services that can be provided to individual subscribers and business subscribers. Such services include voice messaging systems that enable landline or wireless subscribers to record, playback, and forward voice mail messages. However, the ability to provide enhanced services to subscribers of the public switched telephone network is directly affected by the limitations of the public switched telephone network. In particular, the public switched telephone network operates according to a protocol that is specifically designed for the transport of voice signals; hence any modifications necessary to provide enhanced services can only be done by switch vendors that have sufficient know-how of the existing public switched telephone network infrastructure. Hence, the reliance on proprietary protocols and closed development environments by telecommunications equipment providers has limited service providers to vendor-specific implementations of voice and telephony services.
One particular problem in existing voice mail systems is the inability to provide more complex features for voice mail subscribers. For example, conventional voice mail systems are limited to allowing a voice mail subscriber to merely retrieve stored voice mail messages, and possibly forward a voice mail message to another voice mail subscriber within the same voice mail system. However, these conventional voice mail systems do not permit a voice mail subscriber to perform more advanced operations.
Assume that a voice mail subscriber calls into his or her voice mailbox to retrieve messages. During the retrieval of messages, the voice mail subscriber desires to return a call to a party that left the voice mail subscriber a message. Normally the voice mail subscriber would need to terminate the voice mail session and manually call back the party that left the message, resulting in substantial inconvenience to the voice mail subscriber. After completing the call with the party that left the message, the voice mail subscriber normally would need to call back into the voice mail system to access his or her mailbox. Hence the voice mail subscriber needs to endure the added inconvenience of calling back the voice mail system: this inconvenience in repeatedly hanging up and redialing the voice system and/or a party having left a message results in annoyance to the voice mail subscriber, as well as increased toll charges.
U.S. Pat. No. 5,857,013 to Yue et al. suggests the desirability of enabling a mobile telephone user to access his or her associated voice mail system and have the system automatically call a number of a person, having left a message, without leaving the voice mail service. Yue et al. merely suggests use of a Bell South service circuit node, available from ATandT network systems, where the system software is coded in the service logic language within a UNIX environment. Yue et al., however, provides no disclosure of how such a system would be implemented in a telephone network such as a mobile telephone system or the public switched telephone network.
Voice over IP technology is under development as part of an alternative open packet telephony communications network, distinct from the public (circuit switched) telephone network, capable of using packet switched networks for integrating voice, data, facsimile, and Internet services, and the like. New packet telephony voice services are being built from open standards such as The International Telecommunications Union (ITU) Recommendation H.323. Recommendation H.323 defines the components, procedures, and protocols necessary to provide audiovisual communications on local area networks. Recommendation H.323 is based on the Real Time Protocol/Control Protocol (RTP/RTCP) of the Internet Engineering Task Force (IETF), and applies to either point-to-point or multipoint sessions, and references many other ITU recommendations, including H.225 and H.245. Recommendation H.225 specifies messages for call control including signaling, registration and admissions, and packetization/synchronization of media streams. Recommendation H.245 specifies messages for opening and closing channels for media streams, and other commands, requests and indications.
Although voice over IP systems are being deployed to provide point-to-point voice communications services, the current H.323 standard does not provide a direct means for enabling a voice mail subscriber to place an outbound call from a voice mail system, and then return to the voice mailbox after call completion.
There is a need for an enhanced voice over IP voice mail system that enables a voice mail subscriber to initiate an outgoing call from the voice mail system, and return to the voice mail system upon completion of the outgoing call, while maintaining a single voice over IP connection with the voice mail system.
There is also a need for an arrangement that enables a voice mail system to redirect voice over IP connections between a voice mail subscriber and a called party without introducing substantial processing requirements on the voice mail system.
These and other needs are attained by the present invention, where an IP telephony gateway and a voice mail resource enable a voice mail subscriber to place an outgoing call to a destination party from a voice mail session according to the voice over IP (H.323) protocol, and resume the voice mail session upon completion of the outgoing call with the destination party. The IP telephony gateway generates Real Time Protocol (RTP) data streams in response to commands from the voice mail resource, which monitors connections between the voice mail subscriber and the destination party; based on detecting a prescribed condition between the voice mail subscriber and the destination party, the voice mail resource causes the IP telephony gateway to resume the voice mail session, for example using the Empty Capability Set feature in the H.323 standard to perform the outbound call with return capability.
According to one aspect of the present invention, a method is provided in a voice mail resource configured for providing voice mail services to a voice mail subscriber. The method includes establishing a first Real Time Protocol (RTP) data stream for a voice mail session with the voice mail subscriber according to H.323 protocol, initiating a second RTP data stream to a destination party in response to reception of a prescribed command from the voice mail subscriber, and connecting the first and second RTP data streams in response to detecting a first prescribed condition from the destination party. The voice mail session is resumed with the voice mail resource in response to detecting a second prescribed condition between the voice mail subscriber and the destination party. The initiation of the second RTP data stream, and the connecting under the control of the voice mail resource enables the voice over IP voice mail system to perform the outbound call with return capability, enabling the voice mail subscriber to return back to his or her mailbox upon completion of the outbound call.
Another aspect of the present invention provides a system configured for providing voice mail services to a voice mail subscriber over an Internet protocol (IP) telephony link. The system includes an IP telephony gateway configured for establishing Real Time Protocol (RTP) data stream connections according to H.323 protocol, and a voice mail resource. The voice mail resource is configured for establishing a first RTP data stream connection with the voice mail subscriber via the IP telephony gateway for a voice mail session, and initiating a second RTP data stream to a destination party for establishment of a call between the voice mail subscriber and the destination party. The voice mail resource resumes the voice mail session with the voice mail subscriber in response to a detected disconnect condition between the voice mail subscriber and the destination party.
Additional advantages and novel features of the invention will be set forth in part in the description which follows and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The advantages of the present invention may be realized and attained by means of instrumentalities and combinations particularly pointed out in the appended claims.